Dear Karen,
I was also intrigued by this because the descendence from the
mesonichids was the prevailing hypothesis in the whale evolution debate
for some time. This was based on some fossil evidence. Now molecular
evidence links the whales to artiodactyls instead. ALso I believe the
video contained some fossil evidence thas was based on the ankle bones
of the different groups. Ankle bone comparisons linked the whales more
closely with the artiodactyls than with the mesonichids. In terms of
phylogeny, I think it is clear that relationships between organisms are
most clearly explained when you examine BOTH fossil evidence as well as
molecular (DNA) evidence.
I do several fossil comparisons when I cover evolution. Do you have
any cladogram activities?
Mary

I am glad you brought this subject up on channel talk. I was surprised
to learn about this new evidence concerning whales. I had also thought
that the ancestor to whales were the mesonichids. I have a wonderful
PBS movie called Great Transformations, which is one video in a set
called Evolution. This video discussed the belief that whales descended
from a wolf-like creature (mesonichids). Scientists found skeletons in
a desert area that once was part of the a sea (I think the
Mediterranean). By analyzing the skull, specifically the ear bone,
scientists were able to determine that this wolf-like creature had the
same structure as a whale. This structure is only inherent in whales
and therefore had concluded that whales descended from this four legged
animal. This video was obviously made before they used the DNA analysis
to determine that whales most likely descended from the artidactyls.
The scientist in the Rediscovering Biology video who was shocked by the
DNA analysis was the same scientist in the Great Transformation video. I
show this video and as a followup activity I have a group of pictures
that show the physical evolution of whales (from fossils evidence) and
have the students put them in order from oldest to most recent.

I found it quite interesting that scientists now believe that whales are
related to the artidactyls and not the mesonichids as many originally
thought. This also showed that phenotypic evidence (from ankle bone
comparisons) is used in conjunction with molecular evidence (from DNA
comparisons) to trace an organism's phylogeny is the favored approach.
I definitely see the value of cladograms in showing the relatedness of
organisms to each other. I am just curious as to how deeply other
biology teachers delve into this topic. It is quite complex and we are
limited in time. I have a simple cladogram activity that I use, but it
does not go into great detail. How do other biology teachers teach this
subject?
Mary Johnston

Well said. I would like to use your letter to stimulate a discussion on
these topics with my biology classes. Would you be okay with that?

Mr. Quentin Cartier
Biology, Honor Bio, Comp Sci
cartier@ahs.k12.wi.us
Arrowhead High School
262-369-3611 x 1201
>>> "Karen Blaustein" <kblaustein@haverhill-ps.org> 01/04/07 1:47 PM >>>
The concept of a genetic database is very controversial because there
are many pros and cons to each side of the issue. On the positive side,
a genetic database on criminals could help law enforcement officials
track down and convict those individuals that have committed serious
crimes against humanity. Similarly, the database containing genetic
information can overturn judgements or help exonerate individuals that
were wrongly convicted or accused of a crime. However, what individuals
should have to submit to giving their genetic information to the
authorities? Would it only be those individuals who committed a serious
crime and convicted? Or would it be any person would was accused of a
crime, even a misdemeanor? One idea that might be feasable that was
mentioned in the Genomics On-line textbook by Sir Alec Jeffreys. He is
the scientist that first developed genetic fingerprinting in Great
Britain. He suggests "that the actual identity of each individual be
kept in a separate database with high security. Only certain
circumstances, such as a link to a crime, would justify identification
of the individual".
Of course, the cons to genetic databases include the invasion of
privacy. I think the majority of the population should have a choice on
whether they want to know if they have inherited a genetic disorder that
could shorten their life. Also, it is important that insurance
companies cannot use genetic information to deny, charge extra fees or
cancel health or life insurance policies.
In summary, I think that we should take this issue very seriously and
begin to discuss legal regulations that control the possible problems
that could develop as our technology increases.

I am just trying to see how others feel about this ludicrous idea of a
genetic database? I think this is a total invasion of privacy. If we
get to the point where human beings are nothing more than an aggregate
of chromosomes somewhere in a computer file, then I think we are all in
trouble as a society. I can see a lot of discrimination potentially
coming out of this. Maybe an employer won't hire someone with a genetic
predisposition for breast cancer. Maybe, insurance companies will
somehow get access to the information and raise premiums on "high risk"
people. Maybe someone will try and clone someone they are obsessed with
or stalking like a movie star. Of course, these are extreme examples,
but fundamentally I think that we should act now to pass legislation to
prevent things like this from happening in the U.S. As it is people are
stealing identities left and right using basic info. We are leaving
ourselves open to the most personal invasion there is-our very DNA
itself. I for one do not want all my genes catalogued for people to
study. If some people want to volunteer and do it then that is their
choice, but I think a national database of each person's genes is a
really bad idea. What do others think?

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